Electromagnetically induced transparency in two-colour ultracold photoassociation

Abstract

We show how to apply the density matrix approach, including radiative relaxation processes, to calculate the linear optical susceptibility due to a probe laser beam propagated through a photoassociation (PA) system of ultracold atoms. We describe the absorptive and dispersive properties of a two-colour PA system where one laser drives a continuum–bound photoassociative transition and the other laser a bound–bound transition. Taking either of the lasers as a probe and the other one as a control field, we discuss the physical conditions under which electromagnetically induced transparency is possible in such continuum systems. We illustrate our numerical results using two-colour PA in ultracold 174Yb as an example.